Continuous caster molds for changing the width of slabs during casting are known. Typically, such molds have a pair of narrow sidewalls clamped between a pair of broad mold walls. The narrow walls are adjustable by moving one or both of them while the clamping force of the broad walls is relieved. One mechanism for adjusting the spacing and angular alignment of the narrow walls is the twin screw design in which a pair of threaded spindles are attached to each wall at spaced locations. The spindles may be mounted in a fixed housing in which case adjustment of angular alignment is accomplished by driving the spindles to different positions. Examples of this design are shown in U.S. Pat. Nos. 3,292,216 and 3,439,736. Or, the spindles may be mounted in a housing which is tiltable as shown in U.S. Pat. No. 4,270,593. In either case, the spacing required between the spindles and housing permits undesired variation in angular alignment of the mold wall during casting. The tendency for variation in mold wall alignment is especially pronounced when the wall is at greater distances from the housing, i.e. when the spindles extend further from the housing. Also, sufficient tolerance must be provided in the pivotal attachments connecting the spindles to the mold wall to permit the required angular tilting of the wall with respect to the casting direction. Unfortunately, these tolerances also increase the amount of undesired variation in angular alignment.
It is known to use rotatable internally threaded tubular members instead of twin screw spindles for adjusting the spacing of narrow mold walls which are not tiltable. The tubular members tend to enhance the rigidity of the system. Examples of this design are shown in U.S. Pat. Nos. 3,964,727 and 3,710,843. The latter reference shows tubular members mounted in guides referred to as "sliding surfaces" which further enhance rigidity. However, even this latter design would provide sufficient rigidity to eliminate undesired variation in the angular alignment of a tiltable wall during casting.
It is a primary object of the present invention to provide an improved mechanism for significantly decreasing undesired variation in the angular alignment of adjustable narrow walls of a continuous caster mold during casting.
It is another object of the invention to provide a method for adjusting the angular alignment of the narrow walls of a continuous caster mold so as to prevent any significant variation in the angular alignment of those walls during casting.